Adolescence is a period of physical, psychological, and social development. Many older adolescents (18-24 years old) engage in high-risk behaviors such as unprotected sex, multiple sex partners, and drug use. This has caused an increase in the prevalence of human immunodeficiency virus infected (HIV+) adolescents. In addition, many HIV+ adolescents continue to engage in high-risk behaviors leading to a further HIV spread. Current assessments of risky decision-making in adolescents involve self-administered surveys concerning sexual behaviors and drug use. It is imperative that early markers of risky behaviors are identified so that effective interventions are implemented to reduce adolescent HIV transmission. This proposal will utilize non-invasive neuroimaging, such as arterial spin labeling (ASL), to quantitatively measure cerebral blood flow (CBF) within risky decision-making networks. Preliminary ASL studies have demonstrated that HIV diminishes CBF by 60% within risky decision-making areas. We will also use computer based neurobehavioral tests that simulate real-life risky decision making situations. Correlations between neuroimaging and neurobehavioral methods could provide us unique insights into the mechanisms that fuel the adolescent HIV epidemic. The overall direct impact of our research will be: 1) an increase in our knowledge concerning the interaction between risky decision-making and HIV in adolescents 2) the development of early neuroimaging and neurobehavioral markers that assess the impact of HIV infection on risky decision- making networks. These results will assist nurses, clinicians, and public health practitioners in developing interventions that could save lives and reduce the spread of HIV in this vulnerable population.